In manufacturing semiconductor devices or FPDs (Flat Panel Displays), various processes such as a film deposition, an etching, an oxidizing, a diffusing and the like are performed on a semiconductor wafer (which is hereinafter called just a “wafer”) or a substrate for a liquid crystal display that is an object to be processed. In recent years, a substrate processing apparatus called a multi chamber system is used in order to perform these processes with a high throughput.
An apparatus of a cluster type is proposed including a plurality of load ports capable of receiving a FOUP (container) for containing wafers, a plurality of process modules, a storage for temporarily storing processed wafers, and a transfer device for transferring the wafers (for example, see Patent Document 1).
This substrate processing apparatus transfers the wafer to the FOUP placed on the load port, the process module, the storage, and the FOUP placed in the load port in this order. In the process module, a desired process such as an etching process or the like is performed on the wafer. For example, in such a process, remaining gases such as a CF-based gas, HBr gas and the like adsorb on a surface of the wafer after being etched by plasma using the CH-based gas and HBr gas as etching gases. The remaining gases such as the CF-based gas, HBr gas and the like adsorbing on the surface of the wafer react with water in the air when the wafer is carried out of the process module in this state. As a result, a corrosive gas is generated. The corrosive gas is liable to adsorb on the wafer and to corrode the wafer and its surroundings. In particular, the corrosive gas sometimes occurs from the processed wafer because the FOUP loaded in the load port is filled with the air.
Therefore, the wafers are temporarily stored in a temporary storage chamber called a storage before collecting the wafers in the FOUP loaded in the load port. In the storage, the wafers and an atmosphere around the wafers are purged by a gas such as N2 gas or the like. This causes the corrosive gas to be removed from the inside of the storage and prevents the inside and periphery of the FOUP from being contaminated by the corrosive gas when the wafers are collected into the FOUP loaded in the load port.